[Ocfs-devel] Re: [Ocfs-users] Disappointing IMPORT Performance Using 9i RAC with OCFS on Linux

[Wim Coekaerts]

well, you should compare it with rhas21 isntead of rh8

one thing the rhas21 kernel wasn't good at was io grouping, it submitted
really small io's seperately.

which kernel is this e.25 ? 

are you doing loads in parallel on 2 nodes or just a single node and you
just have 2 running ?

you should download the aio patch and try with aio enabled.
lemme dig up the oracle patch you can grab

Wim


On Fri, Nov 21, 2003 at 05:08:58PM -0000, Kevin Miller wrote:
> I am currently involved in setting up a new Oracle environment using 9i
> RAC with OCFS on Linux. Part of the set-up involves importing the
> application schema which comprises 5.5Gb data and 3.7Gb indexes. The
> initial results are disappointing:
> 
> 	Linux non-RAC    Linux RAC-OCFS
>                  60               143
> 
> The results are elapsed time in minutes to complete the full schema
> import (using imp). They are average values from several runs, the
> results from each individual run were fairly consistent. Neither the
> server nor the database were restarted between runs.
> 
> The same dump file was used for each import.
> 
> The top five wait events for Linux RAC-OCFS database are:
> 
> Top 5 Timed Events
> ~~~~~~~~~~~~~~~~~~                                                     %
> Total
> Event                                               Waits    Time (s)
> Ela Time
> -------------------------------------------- ------------ -----------
> --------
> io done                                         1,457,317       5,550
> 51.84
> CPU time                                                        1,628
> 15.20
> log buffer space                                   17,957       1,271
> 11.88
> log file sequential read                            6,174         666
> 6.22
> log file parallel write                            19,632         591
> 5.52
> 
> 
> For the Linux non-RAC database:
> 
> Top 5 Timed Events
> ~~~~~~~~~~~~~~~~~~                                                     %
> Total
> Event                                               Waits    Time (s)
> Ela Time
> -------------------------------------------- ------------ -----------
> --------
> log file sequential read                            6,254       1,280
> 28.25
> CPU time                                                        1,242
> 27.40
> log buffer space                                    8,673         999
> 22.03
> db file scattered read                             51,788         375
> 8.28
> free buffer waits                                     744         330
> 7.28
> 
> 
> First glance would suggest that the Linux RAC-OCFS database is pretty
> much IO bound, but this system has a much higher specification IO
> subsystem then the Linux non-RAC system (see below).
> 
> The specification of the systems is roughly:
> 
> Oracle 9.2.0.4.
> 
> Linux non-RAC
> RedHat 8.0 on Dual 1.8GHz Xeon (with hyperthreading), 1Gb RAM, 2 Ultra
> 320 SCSI disks (not striped or mirrored)
> 
> Linux RAC-OCFS
> 2*(RedHat AS2.1 on IBM x360, Quad 1.5GHz Xeon, 7Gb RAM), fibre connected
> FastT Disk Array
> 
> 
> Any comments?
> 
> (By the way, because I don't do full schema imports very often I'm not
> excited about import performance in its own right, but I am worried that
> the relatively poor performance is symptomatic of a more general issue
> that will affect the application itself)
> 
> 
> Kevin Miller
> Oracle Database Administrator
> Burns e-Commerce Solutions
> 
> 
> 
> 
> 
> 
> 	

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